July 12
— One day, the eyes will be more than just windows to
someone's soul. They'll also be the portal to a person's health.

Nanotechnology
could one day lead to tiny sensors that can be embedded within an astronaut's
blood cells to help monitor for signs of hidden radiation damage that can occur
during extended stays in outer space.
(NASA TV/AP Photo)

At least, that's what Dr. James R.
Baker, Jr. and a team of scientists at the University of Michigan hopes will
happen with the help of nanotechnology — microscopic devices that are thousands
of times thinner than a human hair.

And the concept, an extension of
years of research conducted by Baker and others at the university's Center of
Biological Nanotechhnology to find new ways to detect and fight cancer, sounds
fairly simple.

Microscopic
Monitors

At the heart of the new detection method would be tiny spheres of synthetic
polymers called dendrimers.

Each sphere, or nanosensor, measures a mere five nanometers — or five
billionths of a meter — in diameter. (By comparison, the diameter of a typical
pinhead is a million nanometers wide.) That means billions of nanosensors can be
packed within a small amount of space.

The nanosensors would then be delivered into a human through a skin patch or
even digested with food. Once in the body, the tiny nanosensors embed themselves
within lymphocytes — the white blood cells that provide the body's defenses
against infection and disease.

As lymphocytes fight certain disease and conditions — say a common cold or
the body's exposure to radiation — the protein composition within the cells
change. Each nanosensor, coated with special chemical agents, would fluoresce or
glow in the presence of those protein changes.

And to see the glowing signs of the nanosensors, Baker has an ingenious
solution.

"Our plan is to develop a retinal-scanning device with a laser capable of
detecting fluorescence from lymphocytes as they pass one-by-one through narrow
capillaries in the back of the eye," says Baker. "If we can incorporate the
tagged sensors into enough lymphocytes, a 15-second scan should be sufficient to
detect cell damage."

Backed by NASA for Further Study

The concept hasn't gone far beyond the research stage. But it has warranted
the attention — and funding — of NASA.

The government space agency recently bestowed a three-year, $2 million grant
to Baker and the Center for Biological Nanotechnology to research the concept
further.

"Radiation-induced illness is a serious concern in space travel," says Baker.
"Our goal is to develop a non-invasive system that, when placed inside the blood
cells of astronauts, will monitor continuously for radiation exposure or
infectious agents." Baker believes that the concept could work, given that it's
based on similar nanotechnolgy the team has been working on for cancer
detection.

But he admits that a lot of research has to be done.

For example, he says it's still unclear if the fluorescent glow of the
nanosensors in the white blood cells could be picked up amid the sea of darker
red blood cells. And although he and the research team at the university have
had some success in cell cultures in a lab setting, the real test will be if the
concept works in virto.

Baker says he hopes to begin testing the process with lab animals, perhaps
sometime later this year.